Eric, the Bloodaxe King. He is a king who ruled over Norway around the 9th~10th Century. However, that being said, his reign as a king was not even as long as three years, having only reigned for about that length of time; being driven out from the throne, he escaped to England afterwards and became installed as a mere provincial feudal lord. Nevertheless, what caused his nickname to become well-known was the brutality of massacring his many brothers in order to ascend to the throne during those three years, and the existence of the "witch" Gunnhild, who was rumored to have supported him.[1][2]

Even if his nickname, the Bloodaxe King, was without elegance, and even though he dealt with his brothers in blood, that tyranny of Eric's did not come to a stop. And underneath that, it is said that the "witch" Gunnhild, who married Eric, was operating behind these scenes. Gunnhild was a staunch female magus, but at the same time, she seems to have deeply loved her husband Eric, and after the death of Eric, Gunnhild produced poetry on behalf of giving praise to him. According to those, Eric was the sixth king on the throne after the hero of Scandinavia, Sigmund, and he is said to be welcomed as a great warrior by the Great God Odin... Well, that love for Eric continues on even now whenever Eric is summoned, suddenly being delivered through witchcraft and with a complaint from Gunnhild out of nowhere.[2]

Because Eric is a Servant whose Mad Enhancement has reached B Rank, mutual understanding is fundamentally impossible. However, sometimes, the words of his wife suddenly comes raining down out of nowhere. In order to keep being his Master, it is crucial to properly lend a ear to those words.[1]

The distinction between friend and foe is barely established, and some intelligence exist, but that is simply all that exists. Towards the enemies as well, Eric hastily charges at them. However, there are extremely rare situations where he regains his sanity. On this ocassion, it becomes possible to even conversate with him according to an intermediation done through Gunnhild.[2]

Eric does not possess any cunning at all. He is just like a beast of prey, only trying to slaughter the enemy. He is also very practical, not being picky with respect to his Master. However, it is different with his wife Gunnhild. It is not known how, but if her husband is summoned, she will start talking with his Master through him. She is always complaining about how insulting it is of having been summoned just to be used, and on top of that, as a Berserker. She is what you would call a monster wife.[2]

Gunnhild is able to interact through Eric by speaking with his body, claiming that she would normally kill a Master for daring to use her husband for something like a regular Holy Grail War. Due to the unique circumstances of humanity being in danger, she permits Eric's Master to utilize her husband.[3]

As of the Salomon Singularity, it is revealed that Eric can speak normally and rationally, as seen when he advises Blackbeard to team up with Francis Drake. He says the reason he normally speaks strangely is because of Gunnhild's jealousy, that when he speaks to other women, she occasionally outright curses them. Though he does note that it's set in stone that he will be summoned as a Berserker from now on, he thinks it wouldn't be much of a problem.

Eric acts as an antagonist in the chapter as a crewmember under the command of the pirate Blackbeard and serves to strengthen his ship and Noble Phantasm, the Queen Anne's Revenge. He is confronted by Ritsuka Fujimaru, Mash Kyrielight and Francis Drake, who defeats him, causing him to retreat. They also find his abandoned Viking ship. Eric is faced once again when the party encounters Blackbeard's forces. He is defeated and finally killed by the party during this encounter.

Eric is one of the "Okeanos" Singularity Servants to assist Chaldea against the Demon God Pillars. Eric advises Blackbeard that with the loss in strength of the Queen Anne's due to the loss of Hector, they should call a truce with Francis Drake and instead form an alliance to deal with the constantly resurrecting Demon Pillars.[4]

In his interlude Terror of the Bloodaxe, Eric's wife, Gunnhild, communicates with Chaldea's group through him and permits his utilization as a Servant due to humanity being in danger. However, she tells them that her husband isn't at full strength as his axe needs to be strengthened by the blood of Demonic Beasts to unleash its full power. After slaughtering the monsters summoned by Gunnhild and drinking their blood, Eric's axe is able to reach its full splendor.

Eric possesses the Skill Supporting Shamanism (支援呪術,Shien Jujutsu?), a curse from Gunnhild that causes the parameters of his opponents to be decreased by one rank.[1] His Noble Phantasms are his Half-dead Blood Axe and Bloodbath Crown.

Level 2 Bond
Eric is a king who ruled over Norway during the 9th Century. That being said, he only reigned as a king for little more than three years. After being driven out from the throne, he escaped to England and became a mere provincial feudal lord.

Level 3 Bond
Nevertheless, what caused his nickname to become well-known was the brutality of massacring his siblings in order to ascend to the throne and the existence of the witch Gunnhild, who was rumored to have supported him.

Level 4 Bond

Supporting Shamanism: C

Causes the stats of opponents to suffer a 1 Rank-DOWN.
A curse from Gunnhild, female magus as infamous as her husband.

Level 5 Bond
"Blood-sipping Beastial Axe"
Rank: C Type: Anti-Unit Noble Phantasm
A Magic Beast he once defeated was processed and made out into an axe. It seems that this Magic Beast that was processed into an axe is still alive, and has been surviving by sipping blood.

Interlude
Because this is a Servant whose Mad Enhancement has reached B Rank, mutual understanding is fundamentally impossible. However, sometimes the words of his wife suddenly comes raining down out of the nowhere. In order to keep being his Master, it is crucial to properly lend a ear to those words.